Round balers are used to form bales from stalk-shaped agricultural harvested produce. Such round balers have a bale-forming chamber and associated pressing means. After completion and optional wrapping of a bale with mesh, twine, or film, this bale is ejected out the back of the bale-forming chamber.
If a flat wrapping material, such as mesh or film, is used, this is fed in the prior art by means of a feeding roller that is typically coated with a rubber material or the like, in order to provide a high coefficient of friction. This feeding roller is driven at a circumferential speed that is smaller by a certain percentage than the circumferential speed of the bale-forming means (and thus of the bale), in order to maintain a desired tension in the wrapping material. Such feeding rollers are cylindrical in the prior art (cf. DE 102 11 412 A1) or are provided in any case with knurling in the central area, in order to simplify the introduction of the wrapping material into the bale-forming chamber (DE 100 45 842 A2).
If the bale is not precisely cylindrical due to non-uniform loading of the bale-forming chamber across its width, but instead is conical or barrel-shaped, it might happen that one or both lateral edges of the bale rotate at a slower circumferential speed than that of the feeding roller. This has the result that the wrapping material does not form a sufficiently taut contact against the edges of the bale in order to hold it together, so that the bale ultimately comes apart there.
Similar problems can happen if the storage reservoir roller of the wrapping material continues to turn after the cutting, and loops form at the edge of the wrapping material.